BAGHDAD (AP) — More than 1,000 people were killed in Iraq in July, the highest monthly death toll in five years, the U.N. said Thursday, a grim figure that shows rapidly deteriorating security as sectarian tensions soar nearly two years after U.S. troops withdrew from the country.

Violence has been on the rise all year, but the number of attacks against civilians and security forces has spiked during the Islamic holy month of Ramadan, which began early last month. The increased bloodshed has intensified fears that Iraq is on a path back to the widespread chaos that nearly tore the country apart in the aftermath of the U.S.-led invasion that ousted Saddam Hussein in 2003.

Months of rallies by Iraq’s minority Sunnis against the Shiite-led government over what they contend is second-class treatment and the unfair use of tough anti-terrorism measures against their sect set the stage for the violence.

The killings significantly picked up after Iraqi security forces launched a heavy-handed crackdown on a Sunni protest camp in the northern town of Hawija on April 23. A ferocious backlash followed the raid, with deadly bomb attacks and sporadic gunbattles between insurgents and soldiers — this time members of the Iraqi security forces rather than U.S. troops.

The U.N. Mission in Iraq said 1,057 Iraqis were killed and 2,326 wounded in July, the highest toll since June 2008, when 975 people were killed. The U.N. said 928 of those killed in July were civilians and 129 were Iraqi security forces.

In all, 4,137 civilians have been killed, mostly in Baghdad, and 9,865 wounded so far this year, according to the statement. That was up from 1,684 killed in the January-July period last year.